found a new service for Medusa4 Personal, that converts SHE files to plottable PDFs without the watermark:
[size=16]EN: [b][url]http://eservices.cad-schroer.com[/url][/b]
DE: [b][url]http://eservices.cad-schroer.de[/url][/b][/size]

Here is what they write on their site:

[color=#0000ff] Create Plottable PDFs from Your MEDUSA4 Personal Designs
For only 2.99 per MEDUSA4 Personal design, usually restricted to private use, we will deliver a plottable PDF file for unrestricted (including commercial) use. Please note that only data converted by means of this portal may be used in a commercial manner.

Pay Per Result
This novel approach means that we can continue to deliver the powerful MEDUSA4 Personal product suite free of charge. You only pay once you created the desired design, and benefit by being able to transfer you work into the commercial realm.

Using This Portal
It's free and secure to create a user account for this portal, and you are under no obligation to proceed with a purchase. Once you have registered, you can log in at any time to access your secure personal area, where you can view, edit and download your data. All payments are made by PayPal.